JADE1

JADE1 is a multifunctional nuclear PHD zinc finger protein that integrates chromatin remodeling with tumor-suppressive signaling. It serves as an essential scaffolding subunit of the HBO1 histone acetyltransferase complex, physically bridging HBO1 to histone H3–H4 substrates through an N-terminal domain to increase catalytic efficiency ~5-fold and determine H4K5/K12 acetylation specificity, with its PHD fingers required for synergistic activity; JADE1 also directs HBO1-mediated H3K9 acetylation at Oct4-bound MORE elements during transcriptional regulation (PMID:18684714, PMID:29382722, PMID:41489900). Independent of its chromatin role, JADE1 functions as an E3 ubiquitin ligase that ubiquitylates both phosphorylated and non-phosphorylated β-catenin to antagonize canonical Wnt signaling, an activity negatively regulated by CK1α phosphorylation and positively regulated by pVHL- and NPHP4-mediated stabilization of JADE1 protein (PMID:18806787, PMID:25100726, PMID:12169691, PMID:22654112). JADE1 additionally binds and inhibits AKT kinase activity, promotes apoptosis with concomitant Bcl-2 downregulation, and undergoes Aurora A–dependent phosphorylation driving cell-cycle-dependent chromatin dissociation, collectively positioning it as a tumor suppressor linking chromatin state to proliferative and survival signaling (PMID:23824745, PMID:16046545, PMID:24739512).

1. 2002 High

   The discovery that pVHL physically binds and stabilizes JADE1 protein first linked JADE1 to the VHL tumor suppressor pathway and established it as a potential effector of VHL-dependent renal cancer suppression.

   Evidence Yeast two-hybrid screen, reciprocal co-immunoprecipitation, and metabolic labeling in renal cancer cells

   PMID:12169691

   Open questions at the time

   • Downstream functional consequences of VHL–JADE1 interaction unknown
   • Mechanism of JADE1 destabilization in absence of pVHL not defined
2. 2004 High

   Identification of JADE1 as a nuclear transcriptional co-activator with PHD finger–dependent histone H4 acetyltransferase activity, and mapping the VHL-binding interface to the PHD-extended module, established JADE1 as a chromatin regulator whose stability is controlled by VHL through a specific structural domain.

   Evidence Gal4 reporter assays, HAT activity assays, confocal imaging, Co-IP with TIP60, and VHL domain/mutant mapping by co-transfection and metabolic labeling

   PMID:14973063 PMID:15502158

   Open questions at the time

   • Identity of the HAT catalytic subunit associated with JADE1 not determined
   • Whether JADE1 directly acetylates histones or recruits a separate acetyltransferase unresolved
3. 2005 High

   Demonstrating that JADE1 overexpression promotes apoptosis and suppresses tumor growth while its knockdown rescues these effects established JADE1 as a functional tumor suppressor downstream of VHL.

   Evidence Gain- and loss-of-function in renal cancer cell lines, apoptosis assays, Bcl-2 immunoblot, and nude mouse xenograft

   PMID:16046545

   Open questions at the time

   • Mechanism linking JADE1 to Bcl-2 downregulation unknown
   • Whether tumor suppression requires HAT activity or a separate function unclear
4. 2008 High

   Two parallel advances revealed that JADE1 functions as both an E3 ubiquitin ligase for β-catenin (targeting it for degradation independently of phosphorylation state) and a critical cofactor for HBO1-mediated H4 acetylation, establishing its dual roles in Wnt signaling and chromatin modification.

   Evidence Ubiquitylation assays and β-catenin stability measurements with epistasis to pVHL; siRNA knockdown, in vitro reconstituted nucleosome HAT assays, and PHD deletion mutagenesis

   PMID:18684714 PMID:18806787

   Open questions at the time

   • Whether the E3 ligase and HBO1-cofactor functions are structurally separable not tested
   • Direct structural basis for JADE1 ubiquitin ligase activity not determined
5. 2012 High

   Identification of NPHP4 and polycystin-1 as regulators of JADE1 stability and localization, coupled with the finding that JADE1–HBO1 marks H4K5/K12 during DNA replication and recruits Mcm7, broadened JADE1's functional network to ciliopathy pathways, ADPKD, and replication licensing.

   Evidence Co-IP, co-localization, Wnt reporter assays, zebrafish epistasis for NPHP4; Co-IP, ubiquitination assays with Siah-1, ADPKD mutant mapping for PC1; siRNA/BrdU/ChIP for replication role

   PMID:22654112 PMID:23001567 PMID:23159946

   Open questions at the time

   • Whether JADE1 directly participates in DNA replication licensing beyond HBO1-mediated acetylation unknown
   • Structural basis of NPHP4–JADE1 interaction not resolved
6. 2013 High

   Discovery that JADE1 directly binds and inhibits AKT kinase activity via its N-terminus expanded JADE1's tumor suppressor role beyond Wnt to the PI3K/AKT survival pathway.

   Evidence Kinase activity array, co-immunoprecipitation, domain mapping to AKT catalytic and regulatory domains, soft agar assays

   PMID:23824745

   Open questions at the time

   • Structural mechanism of AKT inhibition by JADE1 not defined
   • Whether JADE1–AKT interaction occurs on chromatin or in the cytoplasm not established
7. 2014 High

   Identification of Aurora A–mediated phosphorylation driving JADE1 chromatin dissociation in mitosis, and CK1α phosphorylation dampening JADE1's anti-Wnt activity, revealed two distinct kinase-dependent regulatory switches governing JADE1 function across cell cycle and signaling contexts.

   Evidence Mass spectrometry of phosphosites with Aurora A inhibitor validation and cell fractionation/live imaging; in vitro CK1α kinase assay, SLS motif mutagenesis, Xenopus secondary axis assay

   PMID:24739512 PMID:25100726

   Open questions at the time

   • Whether Aurora A directly phosphorylates JADE1 or acts indirectly not fully resolved
   • Phosphatases responsible for JADE1 dephosphorylation and chromatin re-association unknown
8. 2018 High

   Biochemical reconstitution established that JADE1 acts as a physical scaffold bridging HBO1 to histone H3–H4, with a 21-residue N-terminal domain increasing catalytic efficiency ~5-fold and determining H4 substrate specificity, resolving the molecular mechanism of JADE1-dependent HAT activation.

   Evidence In vitro HAT assays with recombinant proteins, domain deletion kinetics, and in vivo validation

   PMID:29382722

   Open questions at the time

   • No high-resolution structure of the JADE1–HBO1–nucleosome complex available
   • How JADE1 PHD fingers and the N-terminal scaffold domain cooperate structurally remains unclear
9. 2021 Medium

   Co-immunoprecipitation of JADE1 with 0N4R tau from human brain and genetic enhancement of tau toxicity upon JADE1-homolog knockdown in Drosophila suggested a neuroprotective role for JADE1 in tauopathies.

   Evidence Co-IP from post-mortem human brain tissue, immunohistochemistry of tau aggregates, Drosophila knockdown with rough eye and TUNEL readouts

   PMID:34719765

   Open questions at the time

   • Single study; independent replication needed
   • Whether JADE1 directly modifies tau (e.g., acetylation or ubiquitylation) not tested
   • Mechanism by which JADE1 suppresses tau toxicity unknown
10. 2025 High

    Cryo-EM and ChIP-seq demonstrated that JADE1–HBO1 is preferentially recruited to Oct4 bound at MORE motifs, directing H3K9 acetylation at these sites, revealing a transcription factor–dependent targeting mechanism for the JADE1–HBO1 complex in pluripotency gene regulation.

    Evidence Cryo-EM of Oct4–MORE–nucleosome complex, in vitro HAT assays with reconstituted nucleosomes, ChIP-seq, JADE1 knockdown

    PMID:41489900

    Open questions at the time

    • Resolution of cryo-EM mass attributed to HBO1 complex insufficient for atomic model
    • Whether JADE1 mediates recruitment to other transcription factors beyond Oct4 not explored

• No high-resolution structure of JADE1 alone or in complex with HBO1 and nucleosome exists, the structural basis for JADE1's E3 ubiquitin ligase activity toward β-catenin is undefined, and it is unknown whether the chromatin-remodeling and Wnt-inhibitory functions of JADE1 are coordinated or independent in vivo.
• No atomic-resolution structure of JADE1 or JADE1–HBO1 complex
• E3 ligase mechanism and whether JADE1 itself is the catalytic E3 or recruits one not clarified
• In vivo genetic models (conditional knockout) lacking for definitive tumor suppressor validation in mammals